Calendar of Physics Talks Vienna

Quantum Entanglement of Local Operators

Speaker:

Masahiro Nozaki (Kyoto University)

Abstract:

When the subsystem size is given by a half of the total space, we
have investigated the time evolution of (Renyi) entanglement entropies for those locally excited states which are defined by acting local operator on the ground state. We have found that they approach finite constants in free field theories. We defined (Renyi) entanglement entropies of local operators by final values of those (Renyi) entanglement entropies. We have found that they depend on the details of local operators. We expect that they characterize local operators from the viewpoint of quantum entanglement. They help us study higher dimensional CFTs more. We also found the sum rule which those entropies obey. We also found that these results are interpreted in terms of the relativistic propagation of quasi-particles. We have investigated these quantities in strongly coupled theory.

im Rahmen des Teilchenphysikseminars: We will describe the hadron-collider event shape called transverse thrust within the framework of Soft Collinear Effective Theory. We present a factorized expression for the cross section in the dijet limit, that allows for resummation of the enhanced terms. Using this formalism, we explicitly obtain N2LL resummation accuracy for the first time. The study of transverse thrust is interesting both phenomenologically, and as an excellent illustration of the simplifications that can be achieved by exploiting hierarchies of energy scales via effective field theory methods.

The Temperley-Lieb algebra TL_d has its origin in the study of sl2-modules: Rumer, Teller and Weyl showed (more or less) already in the 30ties that TL_d can be seen as a diagrammatic realization of the representation category of sl_2-modules - providing a topological (and fun!) tool to study the latter.
In this talk I try to explain how one can proof such a realization. Our main tool is “a machine that takes dualities and produces diagrammatic categories”. In particular, we show explicitly how this “machine” works if one feeds it with q-Howe duality – which produces diagrammatic presentations of categories of sln-modules akin to the Temperley-Lieb calculus.
As an application, I give a diagrammatic version of a symmetry of HOMFLY-PT polynomials.
In principal, everything in this talk is amenable to categorification, but we have to stay in the uncategorified world for the moment.

When protons and neutrons are bound together to form atomic nuclei, they exhibit a shell structure (Nobel Prize ‘63) which is characterized by shell closures at fixed proton or neutron numbers (sometimes called magic numbers).
[paragraph omitted due to space limitations]
This talk will focus on recent experimental results of Penning-trap mass measurements at TRIUMF’s Ion Trap for Atomic and Nuclear Science (TITAN) and of laser-spectroscopy work at COLLAPS at ISOLDE. Their relevance for the understanding of the shell-evolution phenomenon and its description in contemporary models of nuclear structure will be discussed.
Full abstract: https://indico.smi.oeaw.ac.at/event/99/

Date:

Wed, 13.05.2015

Time:

17:00

Duration:

60 min

Location:

SMI - Boltzmanngasse 3, 1090 Wien, Seminarraum 2. Stock

Contact:

Dr. Ken Suzuki

Representions of the based loop space

Speaker:

Florian Schätz (Aarhus)

Abstract:

Let X be a connected manifold. It is well known that there is an equivalence of categories between the representations of the fundamental group of X and the flat vector bundles over X.
The aim of the talk is to explain a higher version of this statement, where the fundamental group is replaced by the singular chains on the based loop space of X. Concatenation of loops equips the chains with a multiplication, called the Pontryagin product. The representations of the resulting algebraic structure turn out to be essentially equivalent to something comparably simple, namely the dg category of flat superconnections over X.
The talk is partly based on joint work with Camilo Arias Abad (Universidad Nacional de Colombia, Medellín).